2 * slcanpty.c - creates a pty for applications using the slcan ASCII protocol
3 * and converts the ASCII data to a CAN network interface (and vice versa)
5 * Copyright (c)2009 Oliver Hartkopp
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 * Send feedback to <linux-can@vger.kernel.org>
25 /* To get ptsname grantpt and unlockpt definitions from stdlib.h */
36 #include <sys/socket.h>
37 #include <sys/ioctl.h>
39 #include <sys/types.h>
41 #include <linux/can.h>
42 #include <linux/can/raw.h>
44 /* maximum rx buffer len: extended CAN frame with timestamp */
45 #define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
46 #define DEVICE_NAME_PTMX "/dev/ptmx"
50 static int asc2nibble(char c)
53 if ((c >= '0') && (c <= '9'))
56 if ((c >= 'A') && (c <= 'F'))
59 if ((c >= 'a') && (c <= 'f'))
62 return 16; /* error */
65 /* read data from pty, send CAN frames to CAN socket and answer commands */
66 int pty2can(int pty, int socket, struct can_filter *fi,
67 int *is_open, int *tstamp)
72 char replybuf[10]; /* for answers to received commands */
74 struct can_frame frame;
77 nbytes = read(pty, &buf, sizeof(buf)-1);
79 /* nbytes == 0 : no error but pty decriptor has been closed */
87 /* remove trailing '\r' characters to be robust against some apps */
88 while (buf[0] == '\r' && nbytes > 0) {
89 for (tmp = 0; tmp < nbytes; tmp++)
90 buf[tmp] = buf[tmp+1];
101 for (tmp = 0; tmp < nbytes; tmp++)
102 if (buf[tmp] == '\r')
109 /* check for filter configuration commands */
110 if (cmd == 'm' || cmd == 'M') {
111 buf[9] = 0; /* terminate filter string */
114 /* the filter is no SocketCAN filter :-( */
116 /* TODO: behave like a SJA1000 controller specific filter */
119 fi->can_id = strtoul(buf+1,NULL,16);
120 fi->can_id &= CAN_EFF_MASK;
122 fi->can_mask = strtoul(buf+1,NULL,16);
123 fi->can_mask &= CAN_EFF_MASK;
127 setsockopt(socket, SOL_CAN_RAW,
129 sizeof(struct can_filter));
135 /* check for timestamp on/off command */
137 *tstamp = buf[1] & 0x01;
142 /* check for 'O'pen command */
144 setsockopt(socket, SOL_CAN_RAW,
146 sizeof(struct can_filter));
152 /* check for 'C'lose command */
154 setsockopt(socket, SOL_CAN_RAW, CAN_RAW_FILTER,
161 /* check for 'V'ersion command */
163 sprintf(replybuf, "V1013\r");
164 tmp = strlen(replybuf);
169 /* check for serial 'N'umber command */
171 sprintf(replybuf, "N4242\r");
172 tmp = strlen(replybuf);
177 /* check for read status 'F'lags */
179 sprintf(replybuf, "F00\r");
180 tmp = strlen(replybuf);
185 /* correctly answer unsupported commands */
198 if (cmd == 'P' || cmd == 'A') {
210 /* catch unknown commands */
211 if ((cmd != 't') && (cmd != 'T') &&
212 (cmd != 'r') && (cmd != 'R')) {
217 if (cmd & 0x20) /* tiny chars 'r' 't' => SFF */
218 ptr = 4; /* dlc position tiiid */
220 ptr = 9; /* dlc position Tiiiiiiiid */
222 *(unsigned long long *) (&frame.data) = 0ULL; /* clear data[] */
224 if ((cmd | 0x20) == 'r' && buf[ptr] != '0') {
227 * RTR frame without dlc information!
228 * This is against the SLCAN spec but sent
229 * by a commercial CAN tool ... so we are
230 * robust against this protocol violation.
233 frame.can_dlc = buf[ptr]; /* save following byte */
235 buf[ptr] = 0; /* terminate can_id string */
237 frame.can_id = strtoul(buf+1, NULL, 16);
238 frame.can_id |= CAN_RTR_FLAG;
240 if (!(cmd & 0x20)) /* NO tiny chars => EFF */
241 frame.can_id |= CAN_EFF_FLAG;
243 buf[ptr] = frame.can_dlc; /* restore following byte */
245 ptr--; /* we have no dlc component in the violation case */
249 if (!(buf[ptr] >= '0' && buf[ptr] < '9'))
252 frame.can_dlc = buf[ptr] - '0'; /* get dlc from ASCII val */
254 buf[ptr] = 0; /* terminate can_id string */
256 frame.can_id = strtoul(buf+1, NULL, 16);
258 if (!(cmd & 0x20)) /* NO tiny chars => EFF */
259 frame.can_id |= CAN_EFF_FLAG;
261 if ((cmd | 0x20) == 'r') /* RTR frame */
262 frame.can_id |= CAN_RTR_FLAG;
264 for (i = 0, ptr++; i < frame.can_dlc; i++) {
266 tmp = asc2nibble(buf[ptr++]);
269 frame.data[i] = (tmp << 4);
270 tmp = asc2nibble(buf[ptr++]);
273 frame.data[i] |= tmp;
275 /* point to last real data */
280 tmp = write(socket, &frame, sizeof(frame));
281 if (tmp != sizeof(frame)) {
282 perror("write socket");
294 tmp = write(pty, replybuf, tmp);
296 perror("write pty replybuf");
300 /* check if there is another command in this buffer */
301 if (nbytes > ptr+1) {
302 for (tmp = 0, ptr++; ptr+tmp < nbytes; tmp++)
303 buf[tmp] = buf[ptr+tmp];
311 /* read CAN frames from CAN interface and write it to the pty */
312 int can2pty(int pty, int socket, int *tstamp)
318 struct can_frame frame;
321 nbytes = read(socket, &frame, sizeof(frame));
322 if (nbytes != sizeof(frame)) {
323 perror("read socket");
327 /* convert to slcan ASCII frame */
328 if (frame.can_id & CAN_RTR_FLAG)
329 cmd = 'R'; /* becomes 'r' in SFF format */
331 cmd = 'T'; /* becomes 't' in SFF format */
333 if (frame.can_id & CAN_EFF_FLAG)
334 sprintf(buf, "%c%08X%d", cmd,
335 frame.can_id & CAN_EFF_MASK,
338 sprintf(buf, "%c%03X%d", cmd | 0x20,
339 frame.can_id & CAN_SFF_MASK,
344 for (i = 0; i < frame.can_dlc; i++)
345 sprintf(&buf[ptr + 2*i], "%02X",
351 if (ioctl(socket, SIOCGSTAMP, &tv) < 0)
352 perror("SIOCGSTAMP");
354 sprintf(&buf[ptr + 2*frame.can_dlc], "%04lX",
355 (tv.tv_sec%60)*1000 + tv.tv_usec/1000);
358 strcat(buf, "\r"); /* add terminating character */
359 nbytes = write(pty, buf, strlen(buf));
370 int main(int argc, char **argv)
373 int p; /* pty master file */
374 int s; /* can raw socket */
375 struct sockaddr_can addr;
376 struct termios topts;
381 struct can_filter fi;
383 /* check command line options */
385 fprintf(stderr, "\n");
386 fprintf(stderr, "%s creates a pty for applications using"
387 " the slcan ASCII protocol and\n", argv[0]);
388 fprintf(stderr, "converts the ASCII data to a CAN network"
389 " interface (and vice versa)\n\n");
390 fprintf(stderr, "Usage: %s <pty> <can interface>\n", argv[0]);
391 fprintf(stderr, "e.g. '%s /dev/ptyc0 can0' creates"
392 " /dev/ttyc0 for the slcan application\n", argv[0]);
393 fprintf(stderr, "e.g. for pseudo-terminal '%s %s can0' creates"
394 " /dev/pts/N\n", argv[0], DEVICE_NAME_PTMX);
395 fprintf(stderr, "\n");
400 p = open(argv[1], O_RDWR);
406 if (tcgetattr(p, &topts)) {
411 /* disable local echo which would cause double frames */
412 topts.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHOK |
413 ECHONL | ECHOPRT | ECHOKE | ICRNL);
414 tcsetattr(p, TCSANOW, &topts);
416 /* Support for the Unix 98 pseudo-terminal interface /dev/ptmx /dev/pts/N */
417 if (strcmp(argv[1], DEVICE_NAME_PTMX) == 0) {
419 char *name_pts = NULL; /* slave pseudo-terminal device name */
421 if (grantpt(p) < 0) {
426 if (unlockpt(p) < 0) {
431 name_pts = ptsname(p);
432 if (name_pts == NULL) {
436 printf("open: %s: slave pseudo-terminal is %s\n", argv[1], name_pts);
440 s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
446 addr.can_family = AF_CAN;
448 strcpy(ifr.ifr_name, argv[2]);
449 if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
450 perror("SIOCGIFINDEX");
453 addr.can_ifindex = ifr.ifr_ifindex;
455 /* disable reception of CAN frames until we are opened by 'O' */
456 setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0);
458 if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
463 /* open filter by default */
474 if (select(s+1, &rdfs, NULL, NULL, NULL) < 0) {
479 if (FD_ISSET(0, &rdfs)) {
484 if (FD_ISSET(p, &rdfs))
485 if (pty2can(p, s, &fi, &is_open, &tstamp)) {
490 if (FD_ISSET(s, &rdfs))
491 if (can2pty(p, s, &tstamp)) {